1. Field of the Invention
The present invention relates to an ink jet printing apparatus and an ink jet printing method which perform a printing operation using a print head for ejecting ink. In particular, the present invention relates to a structure for correcting relative print position displacement between a plurality of nozzle arrays.
2. Description of the Related Art
In an ink jet printing apparatus, a displacement is caused in a printing position between a plurality of nozzle arrays provided in a print head due to an error in the manufacture or the like, so that unevenness of density or stripes may appear in a printed image. Japanese Patent Laid-Open No. H11-170501 (1999) describes a technology of adjusting a relative print position displacement between a plurality of nozzle arrays in a conveying direction (sub-scanning direction) of a printing medium. More specifically, Japanese Patent Laid-Open No. H11-170501 (1999) describes the structure for adjusting the displacement of the printing positions in the sub-scanning direction by changing a range of nozzles used in each nozzle array.
As one form of the ink jet printing apparatus, there is known a printing apparatus of using a print head provided with a nozzle array which has a short nozzle arrangement length and ejects color ink such as cyan, magenta and yellow inks, and a black nozzle array which has a longer nozzle arrangement length than that of the above nozzle array. Use of such a print head enables, for example, a problem with ink bleeding in a printing medium such as a print paper to be reduced and also an image in a single black color to be printed at high speeds.
For example, in a case of printing an image using both black ink and color ink, the black nozzle array having the longer nozzle arrangement length is configured to use only a part of the nozzles, and the black ink and the color ink which should be applied to the same area on the printing medium are configured to be ejected by different scans. In consequence, since the black ink and the color ink are applied to the same area with each other by an interval of a fixing time corresponding to approximately one time of scanning, the inks bleed into each other between the black ink and the color ink can be restricted. In a case of printing an image using only the black ink, use of only the black nozzle array having the long nozzle arrangement length allows a printing area corresponding to one time of scanning of the print head to be increased and therefore, the high-speed printing of the image in the single black color can be realized.
However, in a case of printing an image in which an area using both of black ink and color ink and an area using only black ink exist in a mixed manner, when the structure of adjusting the print position displacement between the nozzle arrays as described above is applied as it is, in a case of printing an image of the area using only the black ink, the high-speed printing of the image by the longer nozzle arrangement length may not be realized. More specifically, an adjustment value for adjusting a relative printing position between a plurality of nozzle arrays is applied also to a case of performing a printing operation using only a single nozzle array. Therefore, the above adjustment can prevent the print position displacement possibly caused between the area subjected to printing using both of the black ink and the color ink and the area subjected to printing using only the black ink, and it is also possible to perform the printing with the print position displacement between the plurality of the nozzle arrays being removed in any of the areas. However, in a case of performing the printing using only the single nozzle array, not all of the nozzles in that nozzle array can be used because of the adjustment of the print position displacement. As a result, the high-speed printing of the image by the longer nozzle arrangement length may not be realized.
For example, when adjusting a print position displacement in a sub-scanning direction between the part of the black nozzle array and the color nozzle array, in order to perform a printing operation using a part of the black nozzle array having the longer nozzle arrangement length and using the color nozzle having the short nozzle arrangement length, a use range of the black nozzle array changes in accordance with the print position displacement. Then, in a case of printing an area of the image of a single black color, only nozzles in the use range changing with an adjustment value of the printing position adjustment among the black nozzle array can be used, and therefore, the high-speed printing of the image using all the nozzles in the black nozzle array can not be sufficiently realized.